What causes a bulge to appear on zucchini fruit after it has been picked? This has happened for 2 years now. After being picked, some get a bulge that goes all the way around the fruit.
Bulge on Zucchini Fruit
Certified GKH Gardening Expert
I have not found any research that shows this particular issue you describe.
If the the zucchini has no other issues, i.e. insects or signs of disease, I would not worry. Environmental issues can certainly cause various issues with fruit and vegetable shape.
If the zucchini is mushy, I would not consume and it may be caused by insects or fungus issues.
Practicing crop rotation is important and would recommend this for next year.
Here is a link to refresh you on the growing requirements.